How cells make measurements

  • Date: 08/08/2007

James Keener (University of Utah)


University of British Columbia


A fundamental problem of cell biology is to understand how cells make
measurements and then make behavioral decisions in response to these
measurements. The full answer to this question is not known but there
are some underlying principles that are coming to light. The short
answer is that the rate of molecular diffusion contains quantifiable
information that can be transduced by biochemical feedback to give
control over physical structures. In this talk, this principle will be
illustrated by two specific examples of how rates of molecular
diffusion contain information that is used to make a measurement and a
behavioral decision.

Example 1: Bacterial populations of P. aeruginosa are known to make a
decision to secrete polymer gel on the basis of the size of the colony
in which they live. This process is called quorum sensing and only
recently has the mechanism for this been sorted out. It is now known
that P. aeruginosa produces a chemical whose rate of diffusion out of
the cell provides information about the size of the colony which when
coupled with positive feedback gives rise to a hysteretic biochemical

Example 2: Salmonella employ a mechanism that combines molecular diffusion with a negative feedback chemical network to

Other Information: 

MITACS Math Biology Seminar 2007